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Date:   Thu, 9 Jan 2020 11:05:14 +0000
From:   Morten Rasmussen <morten.rasmussen@arm.com>
To:     Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc:     "Zengtao (B)" <prime.zeng@hisilicon.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Linuxarm <linuxarm@huawei.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] cpu-topology: warn if NUMA configurations conflicts with
 lower layer
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On Mon, Jan 06, 2020 at 03:31:24PM +0100, Dietmar Eggemann wrote:
> Your issue is related to the 'numa mask check for scheduler MC
> selection' functionality.  It was introduced by commit 37c3ec2d810f and
> re-introduced by commit e67ecf647020 later. I don't know why we need
> this functionality?

That functionality is to ensure that we don't break the sched_domain
hierarchy for numa-in-cluster systems. We have to be sure that the MC
domain is always smaller or equal to the NUMA node span.

Morten